Exploratorium: the museum of science, art and human perception

A magnificent site. The Gardening section is wonder to behold, I'd reccomend starting there.

Just Free Stuff! Freebies For Teachers

HomeworkSpot.com: Homework Help, Science Fair Project Ideas, Math Help, Homework Helper

"Simplifying the Search for the Best K-12 Homework-Related Content Online"

Surfing the Net with Kids: Guide to the BEST KID SITES

"... browse the kids sites, view the inspirational Light an Educational Fire movie, subscribe to my free website reviews newsletter, and take advantage of a free trial membership in the Surfnetkids Printables Club."

The Educator's Reference Desk: Resource Guides

"2,000 lesson plans, 3,000 links to online education information, and 200 question archive responses. "